Interstage bleed assembly

ABSTRACT

A two part metering adapter ring, for providing bleed air from the compressor of an aircraft engine, having a plurality of metering air flow passages. The adapter ring is secured to the outer casing stator support member and has a movable seal engaging a member on the inner casing stator support member. A pair of spring members hold the seal in contact with the seal engaging member on the inner casing stator support member.

RIGHTS OF THE GOVERNMENT

The invention described herein may be manufactured and used by or forthe Government of the United States for all governmental purposeswithout the payment of any royalty.

BACKGROUND OF THE INVENTION

In some aircraft engines, bleed air is taken off at the 5th compressorstage and supplied to a plenum for air frame use. The bleed air is takenthrough a metering gap between the outer compressor stator casing andthe inner compressor stator casing. The metering passage is intended topass about 5% of the total compressor air flow to the air frame plenum.It has been difficult to control the area of the bleed passage due tomechanical stackup and thermal growth of the outer and inner casings.Also, the continuous gap allows wakes and swirls in the orifice flowpath which lowers the stall margin.

BRIEF SUMMARY OF THE INVENTION

According to this invention, a sealing member is secured to the outercompressor casing. A seal is provided between the sealing member and theinner compressor casing. The sealing member has a plurality of meteringholes drilled therein which provides for a constant bleed air flow area.Also, by providing bleed holes instead of a continuous gap the wakes andswirls normally present in the bleed air flow path are considerablyreduced.

IN THE DRAWINGS

FIG. 1 is a schematic cut away view of a conventional aircraft enginecompressor bleed air system for supplying the air frame plenum.

FIG. 2 is a schematic cut away view showing the bleed air systemaccording to the invention.

FIG. 3 is a schematic plan view of the metering adapter ring of FIG. 2.

FIG. 4 is an enlarged cut away view of the metering adapter ring of FIG.3.

FIG. 5 is a sectional view of the device of FIG. 4 along the line 5--5.

FIG. 6 is a schematic plan view of split ring seal of FIG. 2.

FIG. 7 is an enlarged schematic plan view of one of the spring membersof the device of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made to FIG. 1 of the drawing which shows a cut awaysection of an aircraft engine compressor having an outer stator supportcasing member 10 and an inner casing stator support member 12. An airflow passage, such as shown at 14, is sometimes provided at the 5thcompressor stage to provide air for air frame use.

According to this invention, as shown in FIG. 2, a metering adapter ring16, shown in greater detail in FIGS. 3-5 is secured to blade supportmember 18. The member 16 is made in two parts 19 and 20, as shown inFIG. 3, to aid in the assembly. The member 21, on the inner casingstator support member 12 provides a sealing surface for a split ringseal 22, shown in greater detail in FIG. 6. The seal 22 is positioned inslot 24 in the metering adapter ring 16. The seal 22 is held in contactwith member 21 by means of two spring members, one of which is shown at26 in FIG. 7. The spring members 26 are positioned in each of the parts19 and 20 of the metering adapter ring 16 prior to assembly. Themetering adapter member ring 16 has a plurality of air flow meteringholes 28 spaced around the member. While only three holes 28 areindicated in FIG. 4, like holes are spaced completely around the adapterring member 16.

In the operation of the apparatus of the invention, the holes 28 in themetering adapter ring 16 control the amount of air flowing from the 5thcompressor to the plenum for air frame use. Any leakage flow, such asaround the ring seal 22, will be negligible compared to the total flowthrough the holes 28. Positioning of the ring seal 22 on the member 21will provide for variations in the spacing between support member 18 andthe member 21 on the inner stator casing member 12, due to variations inmechanical stackup and variations due to thermal growth.

There is thus provided an apparatus for supplying compressor bleed airfor the air frame plenum having a uniform bleed air passage and whichsubstantially eliminates wakes and swirls in the flow passage.

We claim:
 1. In an apparatus for providing bleed air to a plenum for airframe use from the compressor of an aircraft engine wherein the air isnormally taken through a metering gap between the outer compressorstator casing and the inner compressor stator casing: an apparatus forcontrolling the flow of air from the compressor to the plenum,comprising: a two part sealing member secured to the outer compressorstator casing; said sealing member having a portion extending acrosssaid gap between the outer compressor stator casing and the innercompressor stator casing; means for providing a seal between saidsealing member and said inner compressor stator casing; said sealingmember having means for controlling the flow of air from said compressorto the air frame plenum.
 2. The device as recited in claim 1 whereinsaid means for controlling the flow of air from said compressor to theair from plenum consist of a plurality of metering apertures in each ofthe two parts of said sealing member.